CA1326073C

CA1326073C - Wipers for pair of stabilized magnetic disks

Info

Publication number: CA1326073C
Application number: CA000535108A
Authority: CA
Inventors: Richard Howe; Robert D. Freeman; Brent Jenkins; David Jones; Merle Thowe
Original assignee: Iomega Corp
Current assignee: Iomega Corp
Priority date: 1987-02-27
Filing date: 1987-04-21
Publication date: 1994-01-11
Anticipated expiration: 2011-01-11
Also published as: EP0302893B1; JPH01502373A; DE3786401D1; JP2607577B2; US4769733A; EP0302893A4; DE3786401T2; WO1988006790A1; EP0302893A1

Abstract

A B S T R A C T

A magnetic data storage cartridge of the type in which storage disks are rotated by a drive spindle in read/write relationship with two substantially opposed transducers comprising two flexible storage disks; a spacer for coaxially joining said disks in precise spaced relation, said spacer being substantially coaxial of said disk and being of a smaller diameter than said disks; and a flexible inter-disk wiper secured to said cartridge and positioned between said disks to stabilize said disks during rotation.

Description

-BACKGROUND OF THE INVENTIO
The present invention relates to magnetic storage devices which use floppy record disks mounted in a cartridge.
More particularly~ this invention relates to the use of two or more magnetic floppy disks stabilized by a Bernoulli surface.
It is well known that a predictable and constant spacing between a record medium and a transducer is necessary in order to have successful magnetic retrieval and recording of data (i.e., read/wrlte operation). One method of stabilizing the floppy disk is to rotate the disk at high speeds over a flat rigid plate, sometimes called a Bernoulli surface. In this way, an air bearing is created between the flexible magnetic disk and the rigid Bernoulli surface such that a constant and predictable spacing between the Bernoulli surface and the magnetic disk is established. Once the flexible magnetic disk is stabilized, the transducer can be brought into close proximity to the rotating disk at the proper distance from the disk surface. When a transducer "flies over" or is "coupled to" a magnetic disk, as those terms are used in the art, the transducer will penetrate or dimple the flexible medium. The distance between the record surface and the transducer surface can be precisely predicted when this dimpling phenomenon occurs. In this way, the floppy disk is '~ sSabilized by the ~ernoulli surface and t~e spac~ng between the tran~ducer ~nd the disk sur face ~an be precisely predicted and f ixed.
It ~8 desirable ~n the f~eld of magnetic recordlng to 5 achieve ~imultaneou8 acces~ to two magnes$c recording surfaces by two magnetic tran~ducers. ~owever, due to the dimpling of the magnetlc medium as the transducer i8 flown in ~uxtaposition to the diSk, it haq not been pos~ible to access both surfaces of the magne~lc medium s~multaneouqly when two tran~ducer~ are 10 sub~tantially oppo3ed to one another.
It has been shown in t~e prior art that two magnetic record 3urfaces can be acce~sed by two transducer~ by rotating each disk against a ~ep~rate Bernoulli surface. See for example IBM ~echnical Pisclosure ~ulletin, Volume 19, No. 9 of February 1977. Another example of prior art ~hich 8hows two magnetic di~ks acce~sed by two ~eparate transducers i9 Russian Patent No, 594S27. ~owever, in thi-~ di~clo8ure three ~tablli~ing sur~aces are u~ed: one below ~he bottom di~k, one above the top disk, and a 8~nglo 8tabil~zing 8urface which ls held between the di3kS in the 20 region o~ the tran~duc~r.
A dlsadvantage of prior art attempt~ at acce3sing two magnot~c sur~aces slmultaneou~ly ls that prior art application~
are not p~actical in today'~ small and portable magnetic disk drive devices. A~ can be seen from the above cited rsf~rences, the prior art fcequently utilized separate actuators and ~ernoulli 8urface~ for each magnet~c surface. In other case3, large and complox means we~e used to stabll~ze two or mo~e magnetic surfaces.
SUMMARY OF THE_INVENTION
~n accordance with this invention, two or more flexible magnetic disks are coaxially joined and axially gpaced such that a - ~ 1 326073 continuou~ air bearing exists between tbe functional portlon~ of the disk~. An lnter-di~k wlper ~8 interposed between the d$sks and contacts the inner surfaces of both disks, Top and bottom wipers contact the outside surfa~es of the disks. The bottom wiper i~
staked to the inside of the cartridge along one edge. The bottom wiper extends over ~ rib on the inslde of the cartrldge so that the wiper is biased towaed the disk. The flexibllity of the wiper mateeial loads the wiper against t~e di~k. ~h~s obviates what might otherwl~e be a problem of proper 9pacin~ from the inside of the c~r~ridge to the dlsk. The top wlper i3 8ecured by adhesive to ~; the lnside of the cover ~o that it contacts the outer surface of the other di3k.
The wlpers are made of a plastic bac ~liner ~aterial. ~he ~-wipers cover only a portlon of the disk ~urface and are poQlt$oned at the b~ck of t~e cartridge wlth respect to the recording head.
~h~8 produce3 minimum lnterferenc- w~th the stability of the rotating disk9 in She are~ of t~e tran5ducer~.
~ y stabill2ing thè di~k8 with wipers ln accordance with the invention, two substantially opposed tran~ducers can ~lmultaneousl~ acce~3 tho outer Jùrfaces of two diYk~ without cau~ing sub~tantial deformation of either diYk by the transducer ; posi~ioned adjacent to th~ oppo~ite disk, It is there~ore an ob~ect o~ thi~ invantion to provide a compact and efflcient device foe recording and ret~ievlng data to and from two fl~xible magn~t~c recording ~urface~ s~multaneou81y, It is a further ob~ect of thl8 invention to provide a .~ de~ice for recotdinq and retrievlng data to and from two flexible magnetic d~8ks contalned in a rigid portable cartridge.
It is a 6till further ob~ect of th~s invention to provide a device which u~e~ two ~ubstantially opposed transduCers mounted ' on a common actuaSor foc recordlng and retrievlng data to and from two 1exible magnetic disk~ 8im~1taneously, ~ t is an additlonal ob~ect of thi~ lnventlon to provide a method for rotating two ~lo~ely spaced flexible magnetic disks ~o as to create an outward flow o~ ~ir from between the di~ks ~nd ~tabilizing both magnetic di8ks by ~uxtaposing one of the disk~ to a ~ernoull$ surface.
~ he above and other featurs~ and ob~ects o~ this invention will become more apparent upon consideration of the following preferred embodiment and appended claims.

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~RI13F DESCRIPTION 0~ T~E DRAWINGS
Pig. la is a top plan view of the upper disk;
Fig. lb ls a bottom plan vlew of tbe lower disk~
Fig. lc i~ a cros-~-sectional view of the disk pair taken lS substantiallY along line lc-lc o~ Fig. lb, showing the upper disk ana lower d~4k attached to a centrally mounted dl4k hub~
Fig. 2 ls ~n exploded perspective view of the disk cartr~dgc whlch shows the int~rlor sur~ace~ of the cartridge And the disks contalned wit~in the cartr~dge, Pig. 3 ls a perspectlve vi~w from above o~ the a~sembled cartrtdse and a fragmentary perspeotive view of a disk drive in - which lt is used, where the relative positions of each is shown ~u~t pr~or to insertion of the cartridge into the drive.
Fig. 4 is a cut away perspectlve view of a disk dr~ve from below, which show~ the ~s~embled cartrldge partlally inserted into th~ disk drive.
Fig. Sa is a cross-sectional view o~ the centcal portion of the assembled cart~idge as ehc disk palr i8 spinninq at high ~peed, -Fig. 5b is a diagrammatic view of the disk pair in read/write relationship to a pair of opposed transducers as the disk pair is spinning at high s?eed.
Fig. 6 is an exploded perspective view of the disk cartridge made according to the ?referred embodiment of this invention which shows the interior surfaces of .he cartridge and the disks contained within the cartridge.
Fig. 7a is a top jplan view of the disk hub made according to the preferred embodiment of this invention.
lb Fig. 7b is a bottom plan view of the disk hub made according to the preferred embodiment of this invention.
Fig. 7c is a c.oss-sectional view th.ough the cen.e- of the disk hub taken substantially along the lines 7c-7c of Fig.
7b.
Fig. 8a is a cross-sectional view of the central portion of the assembled cartridge made according to the preferred embodiment of this invention as the disk pair is spinning at high speed.
Fig. 8b is a diagrammatic view of the disk pair according to the preferred embodiment of this invention in ~`~ read/write relationship to a pair of opposed transducers as the disk pair is s~inning at high speed.
DETAILED GESCRIPTION
Figs. 1-5 show an embodiment of a disk drive claimed in Freeman, Bauck and Jones Canadian application Serial No. 53S,llO
filed 21 April, 1987 and assigned to Iomega Cor?oration.
Included with a descri?tion of this first embodiment is a ~ description of the features co~mon to the preerred embodiment .' .

~ ~ 1 326073 claimed herein. Following thereafter is a description of the preferred embodiment of this invention insofar as it differs from the first embodiment.

-5a-., , - ~ pESCRIPTIO~ OF TN ~IRST E~BOD~ME~Tl 32 6 07 3 In the ~irst embodlment two eoaxially ~olned ma~netic d~sk~ are spun a~a~n~t a Ber~oulli ~urf~ce ~onta~ned within fl rigid cartridge. ~n opening in this cartridge allow3 accesfi by two ~ub~tantially oppo~ed tran8ducers into the cartrldge such that the outer surface of each magnetlc disk can be ~multaneou61y acce3~ed by a ~ep~rate t~ansducer.
~eerring to Pigs.la-lc, the upper magnetlc di~k 14 o~
the ~irst embodiment of this invention i~ ~oined to 8urface 11 of ~0 disk hub 12. Spacer 13 i8 coaxially ~oined ~a~ de~cribed below) to disk 10 and di~k 14. ~sk 10 contains an arr~y of twelve perforations 15 equally spaced ~rom one another and equidi~tant from the cen~er of disk 10. When dl9k 10 and diBk 14 are rotated together on disk hub 12 at high speed~, apertures 15 allow air to move radially out from between di~k 10 and disk 14. The flow of ai~ shown by the arrows marked ~IR in Fig. 5a. ~n the preferred embodiment of this inventlon, dlsks 10 and 14 have nominal dimenRions equivalent to th~ ~tandard 5.25 inch ~MYLAR~
' floppy disks widely u~ed in the indu4try.
.. 20 In order to achleve the proper flow of air from between di~k 10 and di8k 14, the thickness of disk spacer 13 is of critical importance. While the exact thlc~ness will be a function of parameters such as the type of transducer~ used, the rate o~
rotation of the di~ks, the thickness of the disks, diameter of the . 25 diJk~, and others, the disk spacer ~hould be approxlmately 0.25 mm thick for a standard disk thlckness of ap~roximately 0.lmm. In addition, the disk ~pacer is not ~o large in diameter ~o as to impede the flow of alr into apertures 15 or to engage the magnetically functlonal portion of either di~k: for example, the outer diameter o disk spacer 13 i~approximately the ~ame as the .

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outer diameter of disk hub 12. Disk spacer 13 is preferably integrally joined to disks 10 and 14 in order to achieve the most precise s?acing between the disks, as more fully disclosed in Jones, Bauck and Freeman co-pending Canadian a~plica.ion Serial No. 535,111, filed 21 April, 1987 and assigned to Iomega Corporation.
According to the first embodiment of this invention, disks 10 and 14 are contained in a rigid cartridge 20. Fig. 2 is an exploded perspective view of cartridge 20 showing: the inside surface of cartridge top 21, he inside surface of cartridge bottom 22, and dis~c pair 10 and 14. In assembled form, disks 10 and 14 are contained within the chamber formed by joining cartridge bottom 22 and cartridge top 21. The cartridge bottom 22 has an opening 23 extending from its leading edge 24A to a point short of the center of the cartridge. The cartridge top 21 contains a Bernoulli surface 35 on its inside face which substantially inscribes a circular area therein. Cartridge top 21 has an opening 33 which, in assembled form, is coincidental with the opening 23 in the cartridge bottom 22 and extends from the leading edge 24B of cartridge top 21 to a point beyond the center of the cartridge.
Referring to Figs. lc and 2, the lower surface of disk hub 12 has a circumferential rim 25. A concentric knob 26 extends from the lower surface of disk hub 12 and to the zlane formed by the circumferential rim 25. The lower surface of disk hub 12 sits in a dish-like opening 27 in cartridge bottom 22.
The center of opening 27 is substantially in line with the center line of opening 33 in cartridge top 21 when the cartridge is assembled. Concentric knob 26 se.ves .o z ovide a low friction .~

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upward force on knob 26, thus assuring that the outer surface of disk 14 is urged towards Bernoulli surface 35. The resilient member can be an elastomeric disk as shown, a domed shape spring or any other device which serves this purpose. When motor spindle (Fig. 4) enters cartridge 20 through aperture 33 in cart-ridge top 21 and rotates disk hub 12 at speeds known to those skilled in the art, an air bearing is formed between the surface of disk 14 Bernoulli surface 35 as shown by the arrows marked AIR
in Fig. 5a. This air bearing serves to stabilize disk 14 as it rotates in juxtaposition to the Bernoulli surface 35. During high speed rotation of the disk pair, centrifugal force causes air to be ejected from between the disks. Evacuation of air from between disks 10 and 14 results in a partial vacuum between the disks wherein the atmosphere surrounding the disks is at a higher pressure than the pressure between the disks. This pressure dif-ferential causes flow of air into openings 15 and then radially out from between the disks which in turn sets up a stabilizing air bearing or cushion of air between disks 10 and 14. In this way, disk 14 is stabilized by the rigid Bernoulli surface 35 in cartridge top 21, and disk 10 is in turn stabilized by rotation in juxtaposition to the stabilized surface of disk 14. In this manner both disks are stabilized by the single ~ernoulli surface.
While this invention is described with respect to an embodiment providing a disk pair, it will be appreciated by those skilled in the art that this invention is not so limited. That is, it may be possible according to this invention to stabilize three or four rotating floppy disks with a single Bernoulli surface.

*,h ~ 1 326073 The air ejected radially from between disks 10 and 14 when the disk pair is rotated at sufficient speed sets up an air bearing between the two disks as disclosed. The rate of rotation necessary to effect this air bearing is a function of several parameters, such as: disk size, aperture configuration, disk thickness, disk diameter, disk spacing, and others. It has been found that speeds as low as 1500 rpm are adequate to produce an effective air bearing between the disks. However, stabilization can be achieved when the disks are rotated at high speeds; for example, at 3000 rpm. Variation of the pertinent parameters to achieve a balance between rotation speed and disk wear is within the scope of this invention. In addition, variation of the shape, size, and number of apertures 15 is also within the scope of this invention, although it has been found that simple round holes as shown are preferred.
Two disks stabilized according to this invention can be accessed for read/write operation by two substantially opposed magnetic transducers simultaneously. Referring to Figs. 3 and 4, a drive spindle 61 (Fig. 4) has access to the interior of the cartridge 20 through opening 33 in the cartridge top 21 and transducers 59 and 60 have access to the interior of the cart-ridge through openings 23 and 33. Drive spindle 61 is coaxially mounted to drive motor 62 for rotation thereby. In the preferred embodiment, disk hub 12 is coupled to drive spindle 61.
Fig. 3 shows cartridge 20 assembled and about to enter disk drive 28 through opening 29. Opening 29 is normally closed by hinged cover 29A which is moved to an open position as -------~ _g_ , l 32~013 cartridge 20 is lnserted lntQ drlve 2B. Once cartridge 20 15fully inRerted into drive 28, tran~ducer~ S9 And 60 are actu~ted tow~rd3 dl~ks lO and 14 and sandWiCh the disks between their su~faces during the read~write funct~on. A proper transducer ~urface in close proximity to the aisk surface causes each disk surface t~ dimple-. Thls phenomenon, ~hown ln ~g. Sb, is kno~n a~ coupling~ t~e disk to the t~ansducer and ls an eYgential feature of ~igh perfor~ance magnetic recotd$ng and retrieval. It i8 therefore apparent that two ~ides o~ A 3ingle flexible magnetic disk could no'c be BimUltaneOU81y ac~essed by ~wo substantially oppo~ed head87 for example, l~ a 5ingle d~sk were u ed, head 5g would interfere with the coupling of head 60, and head 60 would likewi~e interfere with the coupling of head 59, When two ma~netic di~k~ are u8ed acco~dlng to th$s invention, however, the 15 air bear ing cre~ted between the disks as they are rotated serves to ~tabilize the di3k~ a~ well a~ to cUShion ~ach dlsk with ~espect to the other 80 that ~oupllng can take place. In thi~
way, two magnetLc ~urfaces can be slmultaneou81y coupled to two transducer~ in practically the same ~pace re~ulred ~or a ~ngle 20 disk. Both embodlment8 of thi~ invention therefore advantageously utilize a small portable cartridge to house the invention.
Referring once again to Fig. 4, cartridge 20 i~ seen in a c~t ~way perspectlve view from below as lt engages spicule member 40 within di~k drive 28. Disk hub 12A has been cut away from this view in order to more clearly show ho~ the di~ks are aligned and rotated. Drive ~plndle 61 i9 rotatably mounted to spicule member 40. 5picule member 40 contain5 reference surface3 41 which are a preci~e predetermined d$s~ance from the ~ur~ace of dri~e ~pindle 61, When cartridge 20 i8 inserted into disk drive 2~, rails 42A
and 42B in cartridge 20 enga~e reference gurface 41. ~S~ ~haped :
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- ~ 1 326073 resilient members 43 insure continued and firm contact between reference rails 42A and 42B and reference surface 41 while the cartridge is within disk drive 28. This interaction between reference rails 42A/42B and reference surface 41 assures proper planar alignment between the disk pair, the transducers, and the Bernoulli surface.
DESCRIPTION OF THE PREFERRED EMBODIMENT
In the description of the preferred embodiment that follows, features which are generally common to the first embodi-ment of this invention have been designated by the same symbol used to describe the first embodiment. In addition, the pre-ferred embodiment will be described in detail only so far as it differs from the first embodiment described earlier.
Referring now to Fig. 6, an exploded perspective view of cartridge 101 shows the inside surface of cartridge top 111; the inside surface of cartridge bottom 112; inter disk wiper 113 sandwiched by disk pair 10 and 14; and shutter 28. In assembled form, disks 10 and 14 are contained within the chamber formed by the joining of cartridge bottom 112 and cartridge top 111, and shutter 28 is slideably mounted on the cartridge. Bottom disk wiper 114 is heat staked to the cartridge bottom 112 at heat stake points 114A. When in assembled form, the lower surface of disk 10 contacts bottom disk wiper 114. When the cartridge is inserted into the disk drive 28 and rotated thereby, any foreign materials on the underside of disk 10 are wiped away as the disk ~ 1 326073 contacts bottom disk wiper 114. Inter-disk wiper 113 is sandwiched between disk 14 and disk 10 and serves to remove contaminates from between the disk pair as the disk rotates.
Hold down nodes 116 in -lla-;, ; ' ' - ... : , -.
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--~ cartridge top 111 engage hold down nodes 117 in cartridge bottom 112 and hold lnter-disk wiper 113 w~thin She csrtridge and between the disks. Top wiper 115 ~ ~dhefi~vely ~oined to ~ernoulli ~urface 35 and wipe3 the upper 8urface of di~k 14 a-q ~t rotate-Q.
Since each of the wiper~ deso~Ibed above i-q in qontact with a portion of the dlsk pair as it rotates, the plaoement and characteristi 08 of the wiper relatlve to disk pair 10/14 are important features of this invention, In the view shown in Fig .
6, di~k pai~ 10/14 ~8 rotated in the cloc~wise direction when used ~n disk driv~ 2~. A6 mentioned earlier, rotation of the disk pair at proper ~peeds causes an air bearlng to be formed between ~ernoull~ ~urface 35 and upper disk 14 as well a~ between disk 14 and 10, The3e air bearlngs serve to stabilize the floppy di~ks as they rotate and thus allow precise a~d accurate magnetic transduction of the data contained thereon. Since transdu~tion o~
the data ~n both the ~ir~t and ~econd embodiments of this lnvention takes place in the region o~ apertures 23 and 33 in the di~k cartridge, it ~R lmportant that the wipers included ln the cartridge accordinq to thi~ second embo~iment p~oduce m~nimum inter~erence with the stability of the rotatlng di~ks in the region of apertures 2~ and 33. Appl~cant has found that placement o~ tho wlpers 113, 114, and llS in the rear of the cartrldge produce~ minlmum ~nterference with the stability o~ the rotating diJkJ In the area where tran~ducSion occurs. A~ the term i~ used herein, ~he rear o~ the cartr~dge comprises that region of the cartridge which ~s angularly displaced ~rom ~he center llne o~ the apertures 23 and ~3 by greatar than about 90 and less than about 270 from the point of view of the rotatlng disks. It i3 also preferr~d that the top and bottom wipers are made ~rom a suitable wiper lamlnant and that all three wipers are constructed so as be substantially burr and tear free. In addition, the wipers are substantially flat and wrinkle free. Although the exact shape and thickness of each wiper will depend upon the specific other dimensions of the cartridge, the wipers in no event are of a shape or thickness which interferes with the stability of the rotating disks. Applicant has found that use of inter-disk wiper 113 according to the most preferred embodiment of this invention has a tendency to augment the stabilization of the disk pair during high speed rotation. While the exact principle behind this surprising phenomenon is not understood, the result is clearly desirous.
The shape, location, and materials for the wipers in the most preferred embodiment of this invention will now be described. Bottom disk wiper 114 is a quarter moon shaped wiper located in the second quadrant of the cartridge, as measured relative to the disk pair as it rotates past opening 23. Wiper 114 is comprised of a plastic/rayon laminant wherein the plastic acts as a backing material to provide rigidity to the wiper and the rayon provides a textured wiping surface in contact with the disk. In the preferred embodiment, the bottom wiper 114 is approximately 0.40 mm thick and positioned so as to just contact the lower surface of disk 10 when the disk pair rotates. Inter-disk wiper 113 is half moon shaped and is contained in the rear half of the cartridge. The inter-disk wiper is a non-woven rayon/nylon blend. In the preferred embodiment of this invention, the inter-disk wiper is of a thickness approximately twice to the spaced between the disks. In the most preferred embodiment, inter-disk wiper 114 is approximately 0.44 mm thick.

~ 13 --~ 1 326073 - Top wiper 115 is wedge shaped and contained in the second quadrant of the cartridge. This disk wiper is made of the same rayon/plastic laminant used for the bottom wiper 114. In the preferred embodiment, top wiper 115 is of a thickness approximately equal to the spacing between the upper surface of disk 114 and Bernoulli surface 35 during high speed rotation of the disks. In the most preferred embodiment, wiper 115 is also approximately 0.40 mm thick.
Referring now to Figs. 7a through 7c, the relationship between disk pair 10/14 and disk hub 120 is revealed. Disk hub 120 contains two coaxial, axially spaced plateau surfaces: upper plateau 121 and lower plateau 122. Upper disk 14 is mounted to upper plateau surface 121 and lower disk hub 10 is mounted to the lower plateau surface 122. The spacing between the disks is determined by the spacing between the respective plateau surfaces. In this second embodiment, each disk is mounted directly to disk hub 122, thereby eliminating the need for a disk spacer between the disks while maintaining precise spacing between the disks.
In the most preferred embodiment of this invention, it is desirable that disk hub 120 and disk pair 10/14 have substantially the same coefficients of expansion. This is an important feature of this invention since different coefficients of thermal expansion may cause a buckling or warping of one disk with respect to the other. It will be appreciated by those skilled in the art, however, that achieving this objective is a relatively difficult task since the polyester film used for the floppy disk is inherently flexible; on the other hand it is necessary that the disk hub of this invention be relatively rigid and hard.

- Accordingly, it has been dlscovered t~a2t a ~isk hub compri~ed of 20 to 30~ glass filled polycarbonate ha~ sub3tantially the same coefficient of ehermal expansion a~ the polyeste~ film used for the floppy di~k pa~r. Referring now to ~ig. 9A, a cro8s- sectional view of ~he central portlon of the assembled cartridge durin~ h~gh speed rotation made according to the second embodiment of thls ln~ention i~ revealed. Thi~ view reveals the following d~stinctions between the first embodiment and the second embodiment: do~ed 3haped spring member 127A iB used in place o~
elastomerlc disk 27~ of the flr6t embodiment disk hub 120 described earliee ~ 6 used in place of disk hub 12 of the first embodlment; the transltion from cartrldge rail 42B to Bernoulli surface 35 has been rounded from the Rharp angled portion 35a shown in Fig. 5b to a more aerodynamic shape as indicated at 135A
lS in Fig. 9b. Ref~rring now to F~g 9b, which is a diagrammatic view of th~ dl-~k palr in read/write relatlonship to tran~ducers S9 and 60, di~k pair 10/14 ~s rotated generally from ri~ht to left, ~uring the road~write operation, d~sk 10 and di3k 14 each dimple as they move past transducers S9 and 60. ~his dimpling e~fect Z0 causes a de~lectlon or c~rvature of the disk in the area of the tran8ducer. This deflection or non linear movement of disk 14 tends to accelera~e the diYk towards Bernoulli surface 35 as the di~k comes o~f transducer 60. In order to protect the disk ~rom ~ki~king~ or ~bang~ng- into the Bernoulli surface or into the transitlon between the 8ernoulli sueSace and rail 42A, applicant ha3 fo~nd that ~or~ing transition 135A in an aerodynamic shape allow3 stable mov~ment of disk 14 fro~ the coupled to the uncoupled posltlon, This feature not only achieves a more stable coupl~ng beeween the transducer and the disk, but also avolds i -15-- damage to the disk which m~y be calæe~ by a vlolent ~r~Qhing of t~e disk ~nto the sharp angle trans~tion of the flr~t emboalment.
While particular embodlments of thl~ lnvention have been Rhown and de~cribed/ modifiCatlons ~re within t~e true spirit and S scope of this lnvention. The ~ppended claimæ are, there~ore, intended to cover all suoh modifications.

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Claims

1. A magnetic data storage cartridge of the type in which storage disks are rotated by a drive spindle in read/write relationship with two substantially opposed transducers comprising:
two flexible storage disks;
a spacer for coaxially joining said disks in precise spaced relation, said spacer being substantially coaxial of said disk and being of a smaller diameter than said disks; and a flexible inter-disk wiper secured to said cartridge and positioned between said disks to stabilize said disks during rotation.

2. The cartridge recited in claim 1 wherein two said flexible disks comprise a generally planar bottom disk and a generally planar upper disk, said cartridge further comprising:
a bottom disk wiper secured to said cartridge and in contact with the lower surface of said bottom disk; and a top disk wiper secured to said cartridge and in contact with the upper surface of said top disk.

3. The cartridge recited in claim 1 wherein said inter-disk wiper is located at the rear of said cartridge.

4. The cartridge recited in claim 2 wherein said inter-disk, top and bottom, wipers are located at the rear of said cartridge.

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5. The cartridge recited in claim 1 wherein said inter-disk wiper is half-moon shaped and is located in the rear half of said cartridge, in relation to the rotation of said disks past said transducers.

6. The cartridge recited in claim 2 wherein said bottom disk wiper has a quarter-moon shape and is located in the second quadrant of said cartridge in relation to the rotation of said disks past said transducers.

7. The cartridge recited in claim 2 wherein said top wiper is wedge-shaped and is located in the third quadrant of said cartridge relative to the rotation of said disks past said magnetic transducers.

8. The cartridge recited in claim 1 wherein said inter-disk wiper is of a thickness approximately equal to twice the spacing between said disks, and wherein said inter-disk wiper contacts the inner surfaces of said disks.

9. The cartridge recited in claim 2 wherein said bottom wiper is a laminated flexible plastic wiper.

10. The cartridge recited in claim 9 further comprising:
rigid side walls forming a container for said disks;
one of said side walls having a rib on the inside surface thereof extending outwardly from the center of said cartridge;
said bottom disk wiper being staked to said one side wall at two points near one edge of said wiper, said bottom wiper extending over said rib and into contact with said bottom disk whereby said wiper is biased against said bottom disk by the flexibility of said wiper.

11. The cartridge recited in claim 10 wherein said top wiper is attached by adhesive to the inner surface of the other side wall.

12. The cartridge recited in claim 1 wherein said flexible storage disks are magnetic storage disks.

13. The cartridge recited in claim 12 in combination with a magnetic data storage drive having two substantially opposed magnetic transducers.

14. The cartridge recited in claim 13 further comprising:
a Bernoulli surface juxtaposed to a first of said disks so that said disk is stabilized by said Bernoulli surface when said disks are rotated by said drive spindle.